Interested in this topic? You may also want to view these photo galleries:

She said the bird found in Sussex County was severely emaciated with extremely high levels of lead in its blood. It likely was poisoned by eating a carcass with lead ammunition or lead fragments in it, she said.

"This is a common way for bald eagles to ingest lead," she said. Other species, such as vultures and hawks also have suffered from lead poisoning because it is still legal to use lead bullets in hunting – with the exception of waterfowl hunting, for which lead ammunition was banned in the 1990s, Smith said.

Lead poisoning accounts for about a dozen bird rescues each year at Tri-State. Many more get sick and die in the wild, Smith said.

Just like in humans, lead poisoning in birds can cause muscle weakness, paralysis, impacts to the nervous system and death. It is also a neurotoxin that can cause permanent brain damage, according to Smith and the Pennsylvania Game Commission.

Smith said experts at Tri-State use the same treatments and medications used on humans.

"We definitely have been able to get the lead out of their system and release them back into the wild," she said. "But it's usually milder lead poisoning."

Another bald eagle, technically the first rescued bald eagle of 2019, is being rehabilitated by experts at Tri-State Bird Rescue & Research Inc. after its wing was cut by a snare trap in New Jersey, Smith said.

This bald eagle, a juvenile only a few years old, was brought to wildlife experts on Jan. 1.

Nearly three years ago, Tri-State tried to save five bald eagles in Piney Neck near Dagsboro exhibiting signs of poisoning.

A mature female bald eagle that was found disoriented in a field on March 19, 2016, was rehabilitated at Tri-State Bird Rescue & Research and released in Sussex County. The bird is flying from a cage in this photo taken during the release.(Photo: TRI-STATE BIRD RESCUE & RESEARCH)

The number of nesting bald eagles in the Delaware Bay and River basin has steadily increased over the past decade, according to the U.S. Fish & Wildlife Service.

That means Tri-State is now seeing far more eagles; bald eagles account for about 70 of the more than 2,500 avian rescues at the organization every year, Smith said.

"They are definitely becoming a lot more common in the area," she said. "It's great news."

While the bald eagle was selected as the national emblem in 1782, large numbers of eagles were killed prior to federal protections in 1940. That, plus the widespread use of damaging pesticides, led to a severe decline in their population here, according to the Delaware River Basin Commission.

Bald eagle.(Photo: Louis Mason)

“By the 1960s, a single bald eagle sighting along the Delaware River was rare,” according to the Delaware River Basin Commission. Now it is relatively common to see a bald eagle flying near Delaware's waterways.

"They've rebounded so much they're no longer on the endangered species list," Smith said. "It's pretty astounding."

Although the bald eagle is no longer listed as endangered, it's still protected under the Bald and Golden Eagle Protection Act, the U.S. Fish and Wildlife Service says.

Under the act, a felony conviction carries a maximum fine of $250,000 or two years in prison, with a double fine for an organization.

Lisa Smith recommends having patience while waiting for someone to respond, as Tri-State rescuers rely on volunteers. If a volunteer is not immediately available to respond, keep an eye on the bird. If able and comfortable, contain or capture the bird with guidance over the phone from Tri-State experts.